The first tunnels have been dug on the section between Brunnen, Sisikon and Flüelen.
This is a very peculiar part of the Gotthard line because here the track is divided between a so called seegleis, which curls along the extremely steep shore of the urnersee part of the vierwaldstättersee and the so called berggleis, which goes straight through the mountains for the most part. While the Berggleis only goes through 4 tunnels, the older Seegleis goes through 9 tunnels of varying length in only 10 kilometres.
The track splits up here because there was not ernough space left along the shore of the urnersee for the double track expansion, which was undertaken about 60 years after the initial opening of the Gotthard line.
However, both tracks meet shortly at the village of Sisikon, where the Gotthard line also enters Uri, the oldest canton of Switzerland.
The air is full of history here. Directly under the Seegleis track one can make out the Tells-Chapel right on the lake, devoted to the mythical swiss national hero Wilhelm Tell who is said to have jumped ashore from a ship here. Then, on the other side of the lake the Rütli meadow is visible, where the Swiss Eidgenosschenschaft was founded according to the myth of the Rütlischwur.
